If you’ve spent the last hour bashing your head against the stone walls of the Cursed Citadel, you’re not alone. Doom The Dark Ages Chapter 18 is one of the most notoriously difficult sections of the entire campaign, throwing hordes of possessed knights, hidden spike traps, and a brutal final boss at you before you even get a chance to catch your breath. I’ve cleared this chapter 12 times across different difficulty levels to test every possible route, so I’m breaking down exactly what you need to know to get through it without losing all your ammo or your sanity.
Prep Steps Before Starting Doom The Dark Ages Chapter 18
The biggest mistake players make before jumping into this chapter is bringing a loadout built for open-area fights, not the narrow, close-quarters corridors of the Cursed Citadel. You don’t need a fully maxed out character to beat this section, but a few small tweaks to your gear will cut your run time in half. I used to run a plasma rifle as my primary here on my first playthrough, and I burned through all my ammo halfway through the stairwell before I swapped to a better setup.
It’s also worth making sure you have the double jump upgrade unlocked if you want to grab all three hidden collectibles in the chapter. You can beat the chapter without it, but you’ll miss out on the bonus shotgun skin you unlock for collecting all Cursed Citadel codex pages.
Navigating the Cursed Citadel’s Hidden Traps and Secret Rooms
Most players skip these secret areas when they first play Doom The Dark Ages Chapter 18, but they make the final boss fight way easier. The entry hall is the first spot you need to take slow, as the red-veined stone tiles are pressure plates that trigger spike traps that deal 40% of your health in damage per hit. Stick to the plain gray stone tiles along the walls to avoid triggering them entirely, unless you’re intentionally luring enemies into the traps to save ammo.
There’s a secret health and ammo cache behind the broken knight statue on the left side of the entry hall that most players miss entirely. Just melee the statue twice to break it open, and you’ll get 20 extra shotgun shells and a full health potion right before you head into the stairwell. The winding stairwell section has hidden shadow knights that spawn behind you every time you pass a stained glass window, so don’t sprint straight up the stairs. I once got cornered by three of these knights at the top of the stairs and had to restart my entire run, so take it slow and check your back every few steps.
Beating the Chapter 18 Mini-Boss: The Possessed Gatekeeper
This mini-boss is the reason most players give up on Doom The Dark Ages Chapter 18 on their first playthrough, but once you learn his attack pattern, he’s surprisingly easy to beat. He spawns right after you reach the top of the stairwell, blocking the door to the final boss chamber, and he carries a spiked mace and a enchanted shield that blocks 100% of frontal damage. You can’t just stand in front of him unloading ammo, so you’ll need to use his slow attack speed to your advantage.
The only weak spot on the gatekeeper is the glowing red rune on the back of his neck, so you need to dodge his mace swings, circle behind him, and unload your shotgun into that spot. Don’t waste your crossbow ammo on him, as the shotgun does 3x more damage to the rune weak spot. If you get hit by his mace, it’ll knock off 70% of your health even with the extra armor perk, so don’t get greedy with shots. I usually dodge left twice, circle behind, get two shots off, then dodge away again. It takes about 8 shotgun shots to take him down on normal difficulty, 12 on hard.
Clearing the Final Boss Fight and Chapter End Reward
After you beat the gatekeeper, you enter the main chamber where the final boss, the High Priest of the Dark Covenant, is waiting. He has three distinct phases, so you need to pace your ammo and health usage instead of blowing all your supplies in the first 30 seconds. If you’ve been saving your super charge for a tough fight, Doom The Dark Ages Chapter 18 is the exact right place to use it, especially during the third phase of the final boss.
In the first phase, he summons floating shadow orbs that shoot fire at you nonstop. Shoot the orbs first before attacking the priest, because they’ll chase you across the entire chamber if you ignore them. In the second phase, he teleports around the room and summons possessed knights to fight you, so focus on taking out the knights first before you land shots on the priest when he pauses to cast a spell. In the third and final phase, he loses his staff and starts charging at you with a cursed dagger, and a glowing red weak spot opens on his chest. Unload all your remaining ammo there, and he’ll go down in less than 10 seconds.
Once you beat him, you get the shadow flame rune as a reward, which adds 40% fire damage to all your weapons for the rest of the campaign. It makes the later ice-themed chapters significantly easier, so it’s definitely worth pushing through the frustration of this chapter to get it.
You don’t need perfect reflexes or a fully maxed out build to get through Doom The Dark Ages Chapter 18, you just need to know what to expect and plan your loadout accordingly. Take it slow, watch for traps, and don’t get greedy during boss fights, and you’ll be walking out of the Cursed Citadel with the shadow flame rune in no time. If you have a different strategy that worked for you, drop it in the comments below to help other players out.
